Optimization of a solution-chemically derived solar absorbing spectrally selective surface

A previously studied solution chemically derived two layer absorber has been improved by adding a third layer. Simulations done with a thin film program showed that the optimized three layer selective absorber should be composed of an 80% nickel–20% alumina film of 100 nm at the base, a 40% nickel–60% alumina film of 60 nm in the middle and finally a 100% silica film of 85 nm at the top. Experimental results confirmed the computer simulated three layer structure. Prepared absorber consisting of the theoretically found optimized layer structure achieved a solar absorptance, αsol, of 0.97 and a thermal emittance, εtherm, of 0.05.